Machine and method for shaping sheet metal



May 25, 1965 Filed May 26, 1960 United States Patent 3,184,942 MACHHNE AND METHOD FOR SHAPING SHEET METAL William Coolrson, Fareliarn, England, assignor to Coolrson Sheet Metal Developments Limited, London, England Filed May 26, 196i Ser. No. 32,014

Claims priority, application Great Britain, lane 2, 1959,

18,842/59 5 Claims. (Cl. 72179) This invention relates to a machine and a method for shaping sheet metal, and more particularly for forming ribs in sheet metal.

One well known process for forming ribs, such as are required for some forms of roofing sheet in sheet metal, consists of cold rolling, that is to say, passing the flat metal sheet between a pair of shaping rolls, in the nature of plunger and die rollers. There is a tendency on the part of the metal to stretch and break as it passes through a pair of rollers, that tendency increasing (other factors remaining constant) with the extent of deformation imparted by these rollers. Thus, if a comparatively deep rib is required, the sheet is passed between a number of successive pairs of rolls, each pair of which progressively increases the depth of the rib by shrinking or drawing-in the flat metal across the width of the sheet, until the desired depth is achieved in the last pair of rolls.

The object of the invention is to provide an improved machine and method for forming a rib in sheet metal.

The invention provides a machine for forming a rib in sheet metal which includes a pair of forming rolls to form the rib, the arrangement being such that the sheet is in inverted valley section along the line or region of the rib to be formed prior to its entry between the forming rolls to assist in the formation of the rib by the forming rolls.

By such means a rib of comparatively great depth can be rolled in thin sheet metal in a single pass through one pair of plunger and die rolls, instead of with several, as in the known process, and with reduced risk of splitting or tearing the metal. It has been found furthermore that the risk of splitting or tearing the metal is further reduced by the use of comparatively large shaping rolls compared to those in use hitherto.

The valley section may be formed by the action of the forming rolls themselves which are preferably provided with a pair of support flanges or peripheral surfaces disposed at an angle to each other corresponding to the angle of the valley section and arranged to assist in maintaining or forming the valley section.

The machine may include means for assisting the sheet (but not the rib) after the rib has been formed to return to the flat plane. Such means may consist of a tapered support piece being shaped at the receiving end to be able to receive the sheet when in valley section and tapering towards the other end so that the sheet is rendered fiat (save for the rib) in the course of its passage over the support piece. The support piece may conveniently be made in two symmetrical parts, intended to be disposed on either side of the rib.

The invention also provides a method of forming a rib in sheet metal which includes the steps of preforrning the sheet into an inverted valley section along the line or region of the rib to be formed and passing the sheet between a pair of shaping rollers to form the rib.

The machine may include a pair of rolls designed to receive the sheet after the formation of the rib and to assist the valley section (save for the rib) to recover to the flat plane, said pair of rolls assisting also to draw the sheet through the machine and having cooperating guide elements to receive and guide the rib.

The invention also provides a method of continuously "ice forming a longitudinal rib in a metal sheet by means of rib forming rolls (the width of the sheet being substantially greater than the portion thereof from which the rib is to be formed) characterized in that the sheet approaches the said pair of rib forming rolls from a plane substantially lower than the nip of the rolls, in the process the said sheet gradually transforming temporarily to an inverted valley cross-section, the apex of said valley section providing the portion of the sheet from which the deep rib is formed as it passes through the rolls, the valley section (save for the rib) thereafter recovering to the flat plane of the finished profile.

In order that the invention may be clearly understood, a preferred embodiment thereof will now be described by way of example with reference to the accompanying drawings, in which:

FIG. 1 shows in perspective view a pair of forming rolls, a sheet passing through side guides and a pair of rib forming rolls of a machine embodying the invention,

FIG. 2 is an elevation in transverse section of the forming rolls with a metal sheet interposed therebetween, and,

FIG. 3 is a diagrammatic View of one part of a support piece for restoring the flat profile of the portions of the sheet flanking the rib after passing through the forming rolls.

In FIG. 1, a pair of rib forming rolls comprise a die roll 16 and a plunger roll 18. Die roll 16 is mounted on an axis 69 vertically above the axis of plunger roll 18.

The die roll has a pair of peripheral surfaces or support flanges 29 disposed at an angle to each other, one each side of a peripheral concave shaping part or groove 24 formed in the plane of symmetry of the die roll. Similarly the plunger roll has a pair of peripheral surfaces or support flanges 22 disposed at an angle to each other, one each side of a peripheral convex shaping part or rib 26 formed in the plane of symmetry of the plunger roll. Support flanges 22 and shaping rib 26 are designed to mate, except for small gap portion 30, respectively with support flanges Ztl and shaping groove 24 and to cooperate with them in forming a'rib 28 in a metal sheet 71 passing between the rolls.

Side guides or rails 70 of steel or other suitable material are positioned in advance of and in spaced relation to the rolls 16 and 18 to guide the metal sheet 71 into the rolls. The vertical height of the side guides is so chosen that the side guides lie in a horizontal plane below that of the finished profile '72 of the metal sheet, which, as can be seen, is approximately level with the base of the shaping rib 26 at its uppermost point. The side guides are sufficiently long to be able to support between them the metal sheet before it has suffered any deformation by the machine.

The rib 28 is formed in the metal sheet by means of the sheet being drawn along the side guides, across the gap separating the side guides and the rolls 16 and 18 and through the nip of the rolls, subsequently passing to a stage where the metal sheet, save for the rib, recovers to a flat plane.

As the metal sheet is drawn upwards from the plane of the side guides to the level of the nip of the rolls, it is temporarily transformed to an inverted valley cross-section 74 with the apex 14 of the valley cross-section extending for a short distance before entering the rolls. It is from this apex that the rib is formed by the cooperating shaping groove 24 and rib 26. The sheet is progressively shaped by the rolls and upon emerging from the rolls is engaged by two symmetrical parts of a tapered support piece 34 (FIG. 3) disposed on either side of the rib 28 whereby they are bent upwardly into a single plane 72.

The valley cross-section 74 is formed partly by the action of the cooperating parts of the rolls 16 and 18, the angle of the valley cross-section being determined by the dimensions and angles of the pairs of support flanges 20 and 22 and the gap 30 between them.

The separation between the support flanges 20 and 22 is greater towards the plane of symmetry of the rolls than at the other faces of the rolls. At its minimum it is slightly greater than the thickness of the metal sheet to be passed through the machine so that the metal may be drawn into the correct shape without danger of the metal being stretched or torn. As the metal sheet passes through the nip of the rolls, it bears in particular against the crown of the shaping 11b 26 and against the junctions between the support flanges 29 and shaping groove 24.

It has been found that the successful working of the.

machine depends on the correct vertical adjustment of the side guides which controls the vertical rise to be experienced by the metal sheet in reaching the rolls. The appropriate position can be ascertained by simple experiment e.g., by passing a trial sheet between the rib forming rolls and allowing it to assume the inverted valley crosssectional shape in which it is under a minimum amount of constraint.

The rollers are made from suitable tool steel, and it Will be appreciated that they are journalled in end bear ings provided in a frame and driven by any suitable means through the intermediary of gearing; none of these features are shown but their provision will not present any problem to a skilled engineer.

The shafts 69 carrying the main forming rolls 16 and 18 are made smaller in diameter than is usually required for conventional roll forming machines, to give a limited amount of flexibility between the rolls which allows more free drawing in of the metal sheet. By reason of the resilient mounting the metal is only gripped sufliciently to drive it through the rolls.

The main forming rolls 16 and 18, as may be seen from the drawing, are of large diameter which tends to reduce the risk of buckling of the metal and this risk is very real in the formation of a comparatively deep rib, especially if it is to be located at an appreciable distance from the edges of the material. A pair of large rolls with their respective rib and groove forms the rib more gradually, distance for distance (measured along the circumference of the roll) than does a pair of smaller diameter rolls. The requisite diameter of roll will depend upon the depth and shape of the rib to be formed, and the nature and gauge of the sheet material. In the embodiment of the invention described above, the width of the metal strip before its passage through the machine is 30 inches, the height of the rib is 2 inches, the material sheet aluminium of .028 inch gauge and rolls 16 and 18 are 18 inches in diameter and 6 inches wide.

By means of the machine above described the transformation of a flat sheet from, and to, a flat plane forming a deep rib in the process has been accomplished without appreciable undesired permanent deformation or buckling of the flat portions of the sheet each side of said rib, and without any appreciable weakening distortion or stretching of the metal.

Although the present invention has been described with particular reference to specific details, it is not intended that such details shall be regarded as limitations upon the 4 scope of the invention except insofar as included in the accompanying claims.

I claim:

1. A machine for the continuous formation of a relatively deep longitudinal rib in a metal sheet, the width of which sheet is substantially greater than the Width of the portion of the sheet from which the rib is to be formed, said machine comprising a pair of rib forming rolls consisting of a lower male roll and an upper female roll disposed in a vertical plane to engage the sheet intermediate the lateral edges thereof, means in advance of and in spaced relation to the rolls for supporting the sheet at a level substantially lower than the nip of the rolls, whereby the sheet when supported by said supporting means and with the leading end of the sheet seating on the crest of the lower male roll will have its lateral side portions unsupported and progressively transformed into a shape having an inverted valley cross-section, the apex. portion of said valley cross-section providing the portion of the sheet from which the rib is formed as the sheet passes through the rolls.

2. A machine according to claim 1 wherein means are provided following the rib forming rolls for engaging the sheet portions laterally of the rib to restore said lateral portions to a flat plane pofile.

3. A machine according to claim 1 wherein the means for supporting the sheet in advance of the rolls comprise side guides which support the sheet adjacent its lateral edges.

4. A machine according .to claim 1 wherein the male roll has a peripheral rib, the female roll has a peripheral groove and each of Said rolls have conical peripheral supporting surfaces which project laterally of the sides of the rib and groove respectively, the diameter of the supporting surfaces on the lower male roll decreasing with distance from the midplane of the roll and the diameter of the supporting surfaces on the upper female roll increasing with distance from the mid-plane of the roll, said supporting surfaces assisting in the gradual transformation of the sheet into a shape having the valleycross-section.

5. A machine according to claim 4 wherein the respective supporting surfaces on the forming rolls have different angles of taper which provide limited gap spaces therebetween.

References Cited by the Examiner UNITED STATES PATENTS 1,233,732 7/17 Vernon l53--3 2,244,847 6/41 Oeckl et al. 29155 2,518,846 8/50 Wright 15354 2,525,980 10/50 Walters 153-54 2,589,541 3/52 Croson 153-54 2,826,235 3/58 Gudmestad 15354 2,907,369 10/59 Brauer 15377 2,979,806 4/61 Macomber 29-155 3,059,685 10/6 2 Behlen -5 153-77 CHARLES W. LANHAM, Primary Examiner.

WILLIAMv F. PURDY, WHITMORE A. WILTZ',

Examiners. 

1. A MACHINE FOR THE CONTINUOUS FORMATION OF A RELATIVELY DEEP LONGITUDINAL RIB IN A METAL SHEET, THE WIDTH OF WHICH SHEET IS SUBSTANTIALLY GREATER THAN THE WIDTH OF THE PORTION OF THE SHEET FROM WHICH THE RIB IS TO BE FORMED SAID MACHINE COMPRISING A PAIR OF RIB FORMING ROLLS CONSISTING OF A LOWER MALE ROLL AND AN UPPER FEMALE ROLL DISPOSED IN A VERTICAL PLANE TO ENGAGE THE SHEET INTERMEDIATE THE LATERAL EDGES THEREOF, MEANS IN ADVANCE OF AND IN SPACED RELATION TO THE ROLLS FOR SUPPORTING THE SHEET AT A LEVEL SUBSTANTIALLY LOWER THAN THE NIP OF THE ROLLS, WHEREBY 